Boilers

ABSTRACT

A boiler for use with liquid or gaseous fuels. Return flow of combustion gases takes place within the combustion chamber itself by means of one or more passageways formed in the walls of the combustion chamber. A plurality of gas flues are positioned alongside the passageways, and this face permits a ready transfer of gases from the passageways into the flues. Thus, the volume of the combustion chamber depends solely on the combustion of the fuels and a compact, efficient boiler results.

[451 May 23,1972

United States Patent Viessmann 3,460,519 8/1969 Ospeltetal.... 187,200 2/1877 Trump...........

[541 BOILERS [72] Inventor:

274,301 3/1883 Fitzgibbons....

m t. S l 9 oo 1 3 2 oo 8 4 4 [22] Filed:

549,958 Craney Wemicke 1,093,429 4/1914 Jacobs et 3.1...

3,232,280 2/1966 Loebel et Primary ExaminerKenneth W. Sprague Att0mey-Kurt Kelman [57] ABSTRACT A boiler for use with liquid or gaseous fuels. Return flow of [30] Foreign Application Priority Data Nov. 28, 1968 Germany......................P 18 11 349.4 Aug. 28, 1969 19 43 761.7

[52] U.S. [51] Int. 7/12 [58] Field of 122/74, 75, 76, 27, 78, 136, Combustion gases takes place within the Combustion chamber 122/136 149 itself by means of one or more passageways formed in the walls of the combustion chamber. A plurality of gas flues are References Cited positioned alongside the passageways, and this face permits a ready transfer of gases from the passageways into the flues.

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PATENTEH MAY 2 3 I972 SHhU 1 BF 3 Mew PATENTEBMM 23 1972 3, 664. 308

sum 2 OF 3 I Inventor: MUS VlE SMkN V K'GEAIT PATENTED MAY 2 3 I972 SHLEI 3 UF 3 Fig- 7 Fig. 8

In ven tor: HM/S VIESSMMVIV BOILERS This invention concerns improvements in or relating to boilers for the combustion of liquid or gaseous fuels, which comprise a heating medium-carrying boiler housing, containing a combustion chamber, above which are arranged in said housing one or more combustion gas flues connected at the burner end of the housing with the combustion chamber. Such boilers for oil or gas having a water-cooled combustion chamber and combustion gas flues parallel thereto are known, the combustion chambers thereof differing fundamentally in that either the flame escapes at the end of the combustion chamber or the combustion chamber is sealed at that end and the combustion gases and flame flow back as a so-called deflection flame along the outer walls of the combustion chamber, so that the gases escape at the front of the combustion chamber either laterally above or below.

With the combustion chamber open at the back i.e. the first type mentioned above the problem occurs that outside the chamber the gases have to be conducted into a deflection chamber for the flues. These deflection chambers are only accessible with difficulty for repairs. If the rear wall of the deflection chamber is not water cooled it suffers great thermal stressing and therefore wears very quickly.

Single chambers for a deflection flame i.e. of the second type mentioned have the disadvantage that the flame must have a considerable velocity if the deflection of the flame from behind is to be effective throughout the length of the combustion chamber. Experience has shown that flame deflection is only possible up to a certain combustion chamber length. In addition, combustion chambers with a deflection flame cause a considerable resistance. They have a high pressure loss and require high capacity combustion air compressors. Furthermore, if the deflection flow passes through the combustion chamber itself the latter must be made sufficiently large, therefore, in view of the combustion gas flues which are also necessary such boilers must have relatively large external dimensions, which is also necessary if the deflection takes place in a deflection chamber whence the heating gas flues pass back along the combustion chamber and are distributed about same.

In boilers for a deflection flame the combustion gases must escape at the combustion chamber periphery at the front and, if the size of the boiler permits, over the whole periphery of the combustion chamber. Combustion chambers for a deflection flame thus require a very large diameter. If heating gas flues e.g. fire tubes, are arranged round the combustion chambers then, as already stated, the boilers have large external dimensions, which is not only disadvantageous during transportation but also requires correspondingly large spaces for installing the boilers. If the heating gas flues for boilers for deflection flame are only arranged over part of the combustion chamber periphery considerable transfer cross-sections occur in the deflection chamber for the combustion gases from the combustion chamber to the flues. In addition, as numerous boilers and proposals for solving the problem show, it is difficult to deflect high temperature combustion gases escaping at the deflection point to the connecting heating gas flues through per se necessary water-cooled parts.

The present invention therefore results from the necessity of providing a boiler which does not have these disadvantages, that is a boiler in which the size or volume of the combustion chamber is designed with reference only to the combustion of the liquid or gaseous fuels and in which it does not need to be enlarged to accomodate returning flue gases other provision being made for this to take place.

According to the invention there is provided a boiler for use with liquid or gaseous fuel, including a heating medium-carrying boiler housing containing a combustion chamber above which are arranged in said housing one or more combustion gas flues connected to the combustion chamber at the burner end of the housing, said combustion chamber having one or more elongate passageways formed in the upper part of its walls, lying alongside the combustion gas flue(s)and serving in operation to direct gases of combustion from the combustion chamber to the said flues.

Two or more such passageways may be provided, said flue(s) being arranged to lie therebetween. Alternatively, one such passageway may be provided at one side of the combustion chamber, said flue(s) being arranged to lie along side it. Again, one such passageway may be provided centrally in the upper wall of the combustion chamber said flues being arranged on both sides thereof.

In a preferred form of the invention one or more such passageway(s)is/are formed in the lower part of the combustion chamber wall, the chamber preferably being axially symmetrical about a horizontal axis.

As a result the actual combustion chamber volume depends solely on the combustion of the fuels, while the return flow takes place in said passageways located above the combustion chamber and alongside the combustion gas flues. In this way the combustion chamber and therefore the entire boiler can have relatively small dimensions and the walls of the combustion chamber form highly efficient heating surfaces, because in operation they closely surround the flame, and the flame flows continuously along the combustion chamber walls. The return flow of the flame, as stated, takes place neither in the combustion chamber itself nor behind the combustion chamber in a deflection chamber, but instead by upward and, if desired, als'o downward reversal at the rear wall and then, depending on the boiler size, towards the front at the top of the combustion chamber through one or more said horizontal passageways which are, at the top or the bottom, open to the actual combustion chamber.

As a result of these passageways the shape and function of the combustion chamber is maintained. The passageways are naturally dimensioned in such a way that they can take up the complete combustion gas flow volume. The surfaces of the passageways form particularly efficient heating surfaces, since the combustion gases flow along their walls.

The combustion gas flues are arranged alongside or parallel to the return flow passageways. The combustion gases flow more readily from the passageways into the flues than in the conventional deflection flame this process being made easier if the height of the passageways either corresponds to that of the combustion gas flues or is optionally even higher than the flues. This results in more favorable transfer cross-sections from the passageways to the flues. The arrangement and design of combustion chamber, return flow passageways and flues make it possible completely to seal off the combustion chamber at the front and the combustion gases merely flow from the passageways into a frontal transition chamber in front of the flues.

In the boiler according to the invention, without great technical expenditure it is possible to arrange a water-carrying vertical member in front of the mouth of the passageway towards which flow the combustion gases which are laterally deflected to the flues. The cleaning covers or cleaning seals required in front of the flues may thereby be subjected to a relatively small thermal stressing and therefore require thinner insulation.

In order that the invention may be readily understood, certain embodiments thereof will now be described with reference to the accompanying drawings, in which:

FIGS. 1 to 5 are diagrammatic cross sections of various embodiments of boiler according to the invention with the housing removed,

FIG. 6 is a perspective diagrammatic view of a boiler according to the invention showing a frontal collecting chamber in communication with the passageways and the combustion gas flues, and

FIGS. 7 and 8 are views similar to FIGS. 1 to 5 of two further embodiments of the boiler.

In the figures there is shown a combustion chamber 1, a burner feed orifice 2 passageways 3 for the return combustion gases and combustion gas flues 4.

In small boilers according to FIG. 1 only one passageway 3 may be arranged laterally, above the combustion chamber 1. The heating gas flue(s) 4 required with low capacity boilers of this type are arranged laterally alongside the passageway 3. With boilers having a larger capacity a larger passageway 3 can be provided centrally in the upper wall of the combustion chamber as shown in FIG. 2 with the combustion gas flues 4 arranged on both sides. For boilers of an even higher capacity two deflection passageways 3 are provided one on each side of the combustion chamber as shown in FIG. or, as shown in FIG. 3, a third recess 3 may additionally be provided in the center for even larger boilers. More passageways may be provided if desired. The combustion chamber 1 has advantageously an oval or approximately oval cross-section to ensure a good transfer to the recesses. In the boilers shown the passageways 3 have laterally vertical walls. This design would be suitable for boilers having an external cubic shape, as is advantageous with boilers for low furnace heating medium pressures and/or for small capacity boilers.

For larger capacity boilers and boilers with high heating medium pressures, which are generally cylindrical in shape the passageways 3 have curved walls or cross-sections (see FIG. 4). The heating gas flues 4 can be fire tubes or flues of any other appropriate type. According to the invention, large boilers in particular operating under high pressure can be manufactured so advantageously and so reinforced against pressure that it is possible for the combustion chamber at both ends and also the boiler itself to be sealed at the front and back with curved clapper plates, cut in proximity to the combustion gas flues and passageway openings.

However, they can be cut in such a way and joined with the flat plates into which the flues are introduced that high compressive stressing and difficult welding are eliminated.

The invention also offers the advantage that the combustion chamber covers 5 to some extent may be automatically reinforced in that the connection of the passageways 3 or 3 leads to a reinforcing buckle edge 6.

As already stated, the combustion chamber 1 can be sealed off completely except for the burner orifice 2 at the front and above, which can be seen from FIG. 6 showing the transition chamber through which can be seen the combustion chamber cover drawn forward into this area. The combustion gas openings of the flues 4 are accessible from the front via a cleaning aperture 7, whereas in front of the mouths of the passageways water-cooled beams 8 are arranged.

In FIGS. 7 and 8,1 is again the combustion chamber, 2 the burner feed orifice, 3 the passageways opening directly to the combustion chamber, 4 the heating gas flues, 5 the combustion chamber wall and 6 the transition edges of the passageway walls in the combustion chamber cover or in the combustion chamber base, whereby these exemplified embodiments differ from those already described in that they also have passageways formed in the lower part of the combustion chamber wall the boiler being axially symmetrical about a horizontal axis.

The embodiment according to FIG. 8 whows how the lower chamber 12 laterally shielded from the passageways is connected to the upper chamber 13 via a water-carrying beam 9. This beam can also be in the form of a hollow ribbed stamping of the combustion chamber near wall l4.

thereof, 3. a fuel burner feed orifice at one end of the combustion chamber for feeding a gaseous or liquid fuel for combustion into the chamber,

a. the combustion gas flowing from said one end to the opposite end of the chamber and rising into the elongated passageway wherein the combustion gas flow is reversed, and

4. at least one combustion gas flue arranged in the housing and in communication with the passageway near the one end to receive the reversed combustion gas therefrom,

a. the combustion gas flue being arranged above the top cover of the combustion chamber and alongside the passageway.

2. The boiler of claim 1, wherein the top cover of the combustion chamber defines one of the passageways along one of the lateral walls of the combustion chamber, a plurality of said flues being arranged parallel thereto.

3. The boiler of claim 1, wherein the top cover of the combustion chamber defines one of the passageways centrally between the lateral walls of the combustion chamber, a plurality of said flues being arranged parallel thereto on each side of the one passageway.

4. The boiler of claim 1, wherein the top cover of the combustion chamber defines one of said passageways along each lateral wall of the combustion chamber, a plurality of said flues being arranged between the passageways and parallel thereto.

5. The boiler of claim 1, wherein the bottom wall of the combustion chamber defines at least one elongated passageway of narrow width projecting below the combustion chamber and extending the entire length thereof, the combustion fuel flowing from said one end to the opposite end of the chamber and also passing into the elongated passageway in the bottom wall wherein the combustion fuel flow is reversed, and further comprising at least one combustion fuel flue arranged in the housing and in communication with the latter passageway to receive the reversed combustion fuel therefrom, the further combustion fuel flue being arranged below the bottom wall of the combustion chamber and along side the latter passageway, the combustion chamber having a horizontal axis and the passageways and flues being symmetrical about said axis.

6. The boiler of claim 1, further comprising end walls at the ends of the combustion chamber, the end wall at the one end defining a combustion gas outlet for the passageway for transferring the combustion gas therefrom to the flue. 

1. A boiler comprising
 1. a fire box shell,
 2. a combustion chamber having two lateral walls interconnected by a bottom wall and a top cover arranged in the fire box shell, a. the top cover defining at least one elongated passageway of narrow width projecting above the combustion chamber and extending the entire length thereof,
 3. a fuel burner feed orifice at one end of the combustion chamber for feeding a gaseous or liquid fuel for combustion into the chamber, a. the combustion gas flowing from said one end to the opposite end of the chamber and rising into the elongated passageway wherein the combustion gas flow is reversed, and
 4. at least one combustion gas flue arranged in the housing and in communication with the passageway near the one end to receive the reversed combustion gas therefrom, a. the combustion gas flue being arranged above the top cover of the combustion chamber and alongside the passageway.
 2. a combustion chamber having two lateral walls interconnected by a bottom wall and a top cover arranged in the fire box shell, a. the top cover defining at least one elongated passageway of narrow width projecting above the combustion chamber and extending the entire length thereof,
 2. The boiler of claim 1, wherein the top cover of the combustion chamber defines one of the passageways along one of the lateral walls of the combustion chamber, a plurality of said flues being arranged parallel thereto.
 3. The boiler of claim 1, wherein the top cover of the combustion chamber defines one of the passageways centrally between the lateral walls of the combustion chamber, a plurality of said flues being arranged parallel thereto on each side of the one passageway.
 3. a fuel burner feed orifice at one end of the combustion chamber for feeding a gaseous or liquid fuel for combustion into the chamber, a. the combustion gas flowing from said one end to the opposite end of the chamber and rising into the elongated passageway wherein the combustion gas flow is reversed, and
 4. at least one combustion gas flue arranged in the housing and in communication with the passageway near the one end to receive the reversed combustion gas therefrom, a. the combustion gas flue being arranged above the top cover of the combustion chamber and alongside the passageway.
 4. The boiler of claim 1, wherein the top cover of the combustion chamber defines one of said passageways along each lateral wall of the combustion chamber, a plurality of said flues being arranged between the passageways and parallel thereto.
 5. The boiler of claim 1, wherein the bottom wall of the combustion chamber defines at least one elongated passageway of narrow width projecting below the combustion chamber and extending the entire length thereof, the combustion fuel flowing from said one end to the opposite end of the chamber and also passing into the elongated passageway in the bottom wall wherein the combustion fuel flow is reversed, and further comprising at least one combustion fuel flue arranged in the housing and in communication with the latter passageway to receive the reversed combustion fuel therefrom, the further combustion fuel flue being arranged below the bottom wall of the combustion chamber and along side the latter passageway, the combustion chamber having a horizontal axis and the passageways and flues being symmetrical about said axis.
 6. The boiler of claim 1, further comprising end walls at the ends of the combustion chamber, the end wall at the one end defining a combustion gas outlet for the passageway for transferring the combustion gas therefrom to the flue. 